Certain 2-phenylimino, 3-alkyl oxazolidines, compositions and methods of use as herbicides



United States Patent 2,902,356 CERTAIN Z-PHENYLIMINO, 3-ALKYL OXAZOLI-DINES, COMPOSITIONS AND METHODS OF USE AS HERBICIDES 7 Raymond W.Luckenbaugh, Wilmington, Del., assignor to E. I. du Pont de Nemours andCompany, Wilmington, Del., a corporation of Delaware No Drawing.Application May 16, 1956 Serial No. 585,176

'5 Claims. (Cl. 71-2.'5)

This invention relates to a class of 2-phenylimino-3- alkyloxazolidines,and to herbicidal compositions and methods employing these novelcompounds.

The phenylimino-alkyl-oxazolidines that have been found to possessoutstanding herbicidal activity are those represented by the followingformula Iii l2 wherein X and Y are selected from the group consisting ofhydrogen, halogen, and alkyl groups containing less than carbon atoms; mis a positive integer less than 4, that is l, 2 or 3; R R R and R areselected from the group consisting of hydrogen and methyl; and R isanalkyl group containing less than 5 carbon atoms. R is preferablymethyl.

X and Y in Formula 1 above preferably are hydrogen or chlorine. Wherethe phenyl ring is substituted with 1 or more chlorines, the mostpreferred compounds are those in which there is chlorine on the paraposition of the benzene nucleus.

The oxazolidines of the present invention can be prepared in accordancewith the following series of reactions. While specific compounds are setforth in these reactions for illustration purposes, it is to beunderstood that any of the compounds of Formula 1 can be prepared bythis route using appropriate reactants.

"ice

The phenyl hydroxyethyl methylureas employed in Equation 2 can beprepared in accordance with the procedure set forth in Searle and ToddU.S. Patent No. 2,663,-

The reaction of Equation 2 can be carried out advantageously by firstpreparing a slurry of the substituted urea in an inert solvent such asbenzene, toluene, xylene, dioxane, or ether, and then adding dropwise tothe reaction mixture at room temperature a slight excess of an equimolarquantity of thionyl chloride. The rate of addition of the thionylchloride and the temperature of the reaction mass are not critical,although 20-40" C. appears to give optimum results.

The reaction mixture is stirred or heated until hydro gen chlorideevolution practically ceases. The solvent is then removed, such as byevaporation invacuum on a steam bath, yielding in essentially pure formthe phenyl chloroethyl methylurea intermediate reaction product ofEquation 2.

In place of the thionyl chloride, other conventional reagents forconverting an alcohol to an alkyl halide can be used in the reaction ofEquation 2. For example, zinc chloride and hydrochloric acid, phosphorushalides in pyridine, aqueous hydrobromic acid together with sulfuricacid, and the action of potassium or sodium iodide and phosphoric acidare suitable for this purpose.

In carrying out the reaction of Equation 3, the phenyl haloethylmethylurea intermediate prepared in accordance with Equation 2 isdissolved'in alcohol and added rapidly to an equimolar'quantity ofpotassium hydroxide dissolved in alcohol. This mixture is refluxed forseveral hours.

The two heterocyclic isomers prepared in accordance with Equation 3 canbe separated by cooling the reaction mixture to about 05 C. andfiltering. The imidazolidinone precipitates and is removed by thefiltration. The oxazolidine can be separated from the filtrate bycooling to a lower temperature. Alternatively, these isomers can beseparated by an alcohol extraction of the reaction product, since theoxazolidines are more soluble in alcohol than are the imidazolidinones.

Other solvents or alkaline condensing agents can be used when carryingout the reaction of Equation 3. For

example, such solvents as methanol, isopropanol, andmethylal; and suchalkaline condensing agents as sodium hydroxide and triethylamine can beemployed.

The oxazolidines of the present invention are low melt ing crystallinesolids or oils that are characterized by low solubility in water.Illustrative of the compounds of the invention represented by Formula 1above are the following:

1 2-phenylimino-3 methyloxazolidine (2) 2- (p-chlorophenylirnino) 3methyloxazolidine (3 2- 3 ,4-dichlorophenylimino) 3 methyloXazolidine(4) 2 2,4,5 trichlorophenylimino) 3 methyloxazoli- (5) Z-(p-tolylimino)3 methyloxazolidine (6) 2- (p-is opropylphenylimino) 3 methyloxazolidine(7) 2 (p-secbutylphehylimino) 3 mcthyloxazolidine 8) 2-(p-bromophenylimino) 3 methyloxazolidine (9) 2-(p-iodophenylimino)3-mthyloxazolidine l0) 2- (p-fluorophenylimino) 3-methyloxazolidine 1 12- 3,4-dimethylphenylimino 3 methyloxazolidine 12) 2- 3chloro-4-tolylimino) 3-methyloxazolidine 13) 2 3-chloro4-isopropylphenylimino) 3-rnethyloxazolidine 14) 2(3,4-dichlorophenylimino) -3,5-dimethyloxazolidine ( 15 2- 3,4-dich1orophenylimino) -3,4,5-trimethyloxazolidine (16) 2 (3,4dichlorophenylimino)-3,5,5-trimethyloxazolidine (17) 2(3,4-dich1orophenylimino)-3,4,5,5-tetramethyloxazolidine 18) 2-(p-chlorophenylimino) -1-ethyloxazolidine (19)2-(3,4-diehlorophenylimino)-3-isopropyloxazolidine (20)2-(3,4-dichlorophenylimino)-3-butyloxazolidine (212-(p-isopropylphenylimino) -3 -ethyloxazolidine (22)2-(p-isopropylphenylimino) -3-n-propyloxazolidine (23 2- (phenylimino)-3,4-dimethyloxazolidine In order to utilize the herbicidal activity ofthe compounds of the invention to best advantage, they are formulated byadmixture with a carrier material or conditioning agent of the kind usedand referred to in the art as a pest control adjuvant or modifier. Thisprovides formulations adapted for ready and efficient application tosoil, weeds, or unwanted plants using conventional applicator equipment.Thus, the herbicidal compositions of the invention are in the form ofsolutions, dusts, Water dispersible powders, aqueous dispersions, andemulsions.

Pest control adjuvants such as dusts, solvents, wetting, dispersing andemulsifying agents set out in U.S. Patent 2,426,417 can be employed inpreparing the herbicidal compositions of the present invention. Otherwetting, dispersing, and emulsifying agents such as those listed indetail in Bulletin E 607 of the Bureau of Entomology and PlantQuarantine of the US. Department of Agriculture, and such as those setout in an article by McCutcheon in Chemical Industries, November 1947,page 811, entitled Synthetic Detergents can also be used. The preferredherbicidal compositions of the present invention are in the form ofwater dispersible powders. These can be prepared by admixing one or moreof the substituted oxazolidines with a surface-active dispersing agentand afinely divided solid carrier or dust such as talc, pyrophyllite,natural clays, diatomaceous earths and other powdered diluents such asthose setout in the aforementioned US. patent. The surface-activedispersing agent is used in amount sufficient to impart waterdispersibility to the powder. Dust compositions can be prepared bymixing one or more of the substituted oxazolidines with a finely dividedcarrier such as those-set forth in the aforementioned US. patent.

Liquid herbicidal compositions can be prepared by intimately dispersingone or more of the substituted oxazolidines in a conventional liquidherbicidal carrier, such as water or a herbicidal oil. For example,effective liquid compositions can be prepared by vigorously millingtogether a herbicidal oil such as kerosene and a substitutedoxazolidine. Such a liquid composition can be prepared in the form of aconcentrate that can subsequently be extended with a herbicidal oil. Ifan emulsifier is included in the concentrate, it can also be extended tosprayable concentrations with water.

The content of substituted oxazolidines in the herbicidal compositionsof .the invention will vary according to the manner in which and thepurpose for which the composition is to be applied but, in general, willbe from 0.05 to 95% by weight of the composition.

The herbicidal method of the present invention comprises applying asubstituted voxazolidine of Formula 1, ordinarily in a herbicidalcomposition of the aforementioned type, to the locus or .area to beprotected from undesirable plant growth. The active compound is, ofcourse, applied in amount 'sufil'cient to exert the desired herbicidalaction. The applicationcan be made directly upon the locus or v areaandthe vegetation thereon during theperiod of infestation, or,alternatively, the-application can be made in advance of an anticipatedweed infestation.

When applied as a foliar spray ordinarily a dosage of The preferredmethod is to'apply the substituted oxazolidines directly to the soilprior to weed infestation, that is, as a pre-emergence treatment. Whenused in this way it may be desirable to includerother soil pesticides,such as soil fungicides and nematocides. Also, it may be desirable toinclude afertilizer'material in these compositions.

border that the invention'can be better understood, the followingexamplesare given in addition to those set forth above:

Example .1

19.6 parts by weight ofthionylchloride is added drop- Wise over a periodof minutes to a mixture of 29.1 parts by weightof.l-(2-hydroxyethyl)-l-methyl-3-phenylurea and 200 parts'byweightofbenzene. The reaction is slightly exothermic and hydrogenchloride is evolved. After refluxing on a steam bath for 4 hours,hydrogen chloride evolution practically ceases. 1'-(2-chloroethyl)-1-methyl-3-phenylurea' is isolated by evaporation of the so'lvent as aviscous semi-solid, giving a 76% yield.

Analysis.Calcd. for C H CIN O: N, 13.2; Cl, 16.7. Found: N, 13.13,13.26; Cl, 17.41.

A sample of this impure substituted urea is then purified bycrystallizing from ethanol-water to yield essential- 1y pure crystalline1-(2-chloroethyl)-1-methyl-3-phenylurea having a melting point of 99100C.

Analysis.-Calcd. for C I-I ClN O: N, 13.2; C1, 16.7. Found: N, 13.20;Cl, 16.27,'16.'17.

21.3 parts by weight of 1-(2-chloroethyl)-1-methyl- 3-phenylurea isadded gradually to a solution of potassium hydroxide containing 6.6parts by weight of potassium hydroxide in parts of ethanol. The mixtureis stirred and refluxed for two'hours. The hot solution is filtered fromthe potassium chloride, and on cooling,1methyl-3-phenyl-2-imidazolidinone, 10.5 parts by weight, precipitatesfrom the filtrate.

Analysis.'Calcd. for C H N O: N, 15.9. Found: N, 15.81, 15.66.

After the imidazolidinone is removed from the reaction mass byfiltration, the filtrate is diluted with a large volume'of water. 2phenylimino 3 methyloxazolidine separatesand-is isolated by extractionwith methylene dichloride, followed by exaporation of the solvent.

This compound is formulated into a wettable powder of the followingcomposition by combining the dry components, blending in a ribbonblender, micropulverizing in a hammer mill until substantially all ofthe product is below 50 microns in particle size and reblending theproduct in a ribbon blender:

Percent 2-phenylimino-3-methyloxazolidine 50 Dry synthetic calciumsilicate (Micro-eel 805) 48 Alkyl aryl sulfonate 1.75 Methyl cellulose0.25

When applied at a rate of 40 lbs/acre of active ingradient, thiscomposition gives excellent control of an assortment of weeds such asbroomsedge, crabgrass, yellow fox tail, annual ragweed and quack grass.

Example 2 A mixture consisting of 60.0 parts by weight of 3-(3,4-dichlorophenyl)-1-(2-hydroxyethy1) 1 methylurea and 400 parts by weightof benzene is treated with 29.8 parts by weight of thionyl chloride inaccordance with the procedure of Example 1. Crude 1-(2-chloroethyD-3-(3,4-dichlorophenyl)-1-methy1urea, 54.5 parts by weight, is isolatedas abrown solid by evaporation of the benzene solvent.

A part of this crude solid is recrystallized from ethanolwater to giveessentially pure 1-(2-chloroethyl)3-(3,4-

.. dichlorophenyl)-1-methylurea having a melting point of 10 to 60pounds per acre will be used.When applied to the soil as a pre-emergencetreatment, a dosage-of about 4 to 20 usually is employed.

AnalysiS.Calcd. for C H Cl N O: N, Cl, 37.9. Found: N, 9.98, 9.93; CI,36.79, 36.90.

54.5 parts by weight of the thusly prepared 1-(2-chloroethyl)-3-(3,4-dichlorophenyl)-1-methylurea is dissolved in 75parts by weight of alcohol. This is added to a solution of 12.7 parts byweight of potassium hydroxide (85%) in 200 parts by weight of alcohol.The mixture is refluxed for two hours, cooled to 20 C., and filtered.Essentially pure 3(3,4-dichlorophenyl)-1- methyl-Z-imidazolidinone, 20parts by weight, M.P. 157- 157 .5 C., is obtained after washing thepotassium chloride from the precipitate with water.

After removing the imidazolidinone from the reaction mass by filtration,the filtrate is diluted with a large volume of water.2-(3,4-dichlorophenylimino)-3-methyloxazolidine separates from thesolution, and is removed by filtration. After the product is air dried,there is obtained 12 parts by weight of2-(3,4-dichlorophenylimino)-3-methyloxazolidine melting at 4547 C.

Analysis.-Calcd. for C H Cl N O: C, 48.0; H, 4.08; Cl 29.0; N, 11.4.Found: C, 49.23, 49.10, 49.66; H, 4.22, 4.05, 4.39; N, 11.30, 11.06; Cl,28.28.

The thusly'prepared substituted oxazolidine is then formulated into thefollowing dust herbicidal composition by mixing the active componentWith the adsorptive diluent, micropulverizing the mixture, and thenextending the mixture with the principal diluent followed by blending ina ribbon blender:

Percent 2-(3,4-dichlorophenylimino)-3-methyloxazolidine 10 Syntheticsilica (Hi-Sil) 10 Talc 80 These mutually soluble components are stirredtogether until a homogeneous solution results. The solution can beemulsified in water and diluted to use concentration or it can bediluted with a herbicidal oil such as Diesel oil and sprayed directly.

Example 3 24.7 parts by Weight of1-(2-chloroethyl)-3-(p-chlorophenyl)-1-methylurea is dissolved in 75parts by weight of ethanol. This is added to a solution of 6.6 parts byweight of potassium hydroxide (85%) in 200 parts of ethanol.

The mixture is refluxed for two hours, cooled to and filtered, removingthe imidazolidinone reaction product.

The filtrate is further cooled using a Dry Ice-acetone bath. Essentiallypure 2 (p chlorophenylimino)-3 methyloxazolidine separates from thesolution and is removed by filtration.

The thusly prepared substituted oxazolidine is formulated into thefollowing dust herbicidal composition in accordance with procedure ofExample 2:

Percent 2-(p-chlorophenylimino)-3-methyloxazolidine 20 Diatomaceoussilica (Celite 209) 3O Pyrophyllite 50 Example 4 31 parts by weight ofthionyl chloride is added dropwise over a period of 15 minutes to amixture of 65 parts by weight of3-(3,4-dichlorophenyl)-1-ethyl-1-(2-hydroxyethyl)urea and 500 parts oftoluene. The mixture is let stand several days at room temperature,during which time an oily layer forms on the bottom of the vessel. Theoily bottom layer is then separated and the toluene removed byevaporation. The resulting 1-(2- chloroethyl)-3-(3,4'- dichlorophenyl) 1ethylurea (61 parts) is a viscous yellow oil, n 1.5885. I

The oil is dissolved in parts of ethanol. To this solution there isadded 13.4 parts of potassium hydroxide in 200 parts of ethanol. Themixture is stirred and refluxed for two hours. The hot solution isfiltered from the potassium chloride. On cooling the imidazolidinoneseparates and is removed by filtration. On further cooling of thefiltrate with a Dry Ice-acetone solution,2-(3,4-dichlorophenylimino)-3-ethyloxazolidine separates, and is removedby filtration. The product is air dried. There is obtained 17 parts byweight melting at 54-5 6 C.

Analysis.Calcd. for C H Cl N O: N, 10.8; C1, 27.4. Found: N, 10.75,10.90; Cl, 27.06, 26.75.

This substituted oxazolidine is then formulated into the followingpellet herbicidal composition by intimately mixing thecomponents with avery small amount of water in a ribbon blender and extruding theresulting paste under high pressure through a g-inch diameter die andcutting the extruded Worms into Ai-inch lengths:

Percent 2- 3,4-dichlorophenylimino) -3-ethyloxazo1idine 25 Anhydroussodium sulfate 10 Non-gelling kaolin clay 65 Examples 5 to 17 ExampleAmts,

N 0. Product Urea Reaetant Parts by Weight 5 2-(2,4,5 -triehlorophen-.1-(2-chloroethyD-1- 31.6

yhm1no) -3-methylmethyl-3-(2,4,5-trioxazolidme. chlorophenyDurea.

6 2(psopropylphenyl- 1-(2-chl0roethyl)-3-(p- 25.5

1m no)-3-methyloxacumenyD-l-rnethylzolldme. urea.

7 2( p-hromopheny1- 3-(p-bromophenyl)-1- 24.7 1mmo)-3-methyloxa-(2ch1oroethyD-lzohdrne. methylurea.

8 2-(3, 4-d 1methylphen- 1-(2chloroethyD-1- 24.1

yhmmo)-3-methylmethyl-3-(3,4-xylyl) oxazolidine. urea.

9 2-(3-ehloro-4-isopro- 3-(3-chl0ro-p-eumenyl)- 28.9

pylphenylimino)-3- 1-(2-chloroethyl)-lmethyloxazolidino. methylurea.

l0 2-phenylimino-3,4 1-(2rchloro-1-methyl- 22.6

dimethyloxazohdine. ethyl)-1methyl-3- phenylurea.

11 2-(3, 4-d1chlorophen- 1-(2-chloropropyD-3- 29.6

yl1mino) -3,5-dimeth- (3,4-dichlorophenyl)- yloxazohdine. l-methylurea.

12 Z-(p-fiuorophenyl- 1-(2-ch1oro-1-methyl- 27.3

imino)-3-ethyl-4,5 propyD-l-ethy1-3- dimethyloxazolidine.(p-fluorophenyl) urea.

13 2(p-iodophenylimino)- 1-(2-ch1or0-1-methyl- 36.7

3,4,5-trimethyloxapropyl)-3-(p iodozolidine. phenyD-l-methylurea.

14 2-(ortho-ethylphenyll-(2chlor0-1,2-dimeth- 28.3

imino)3,4,5,5-tetraylpropyl)-3-(o-ethylmethyloxazolidine.phenyl)-l-methylurea.

15 2-(p-n-butylphenyll-(p-n-butylphenyD- 28.3

imino)-3-ethyloxa- 3-(2 ChIOI'OQthY1 -3' zolidine. ethylurea.

16 2-(3,4diehlorophenyl- 1-(2-eh1oroethyD-3-(3, 31.0

imino)-3-isopropyl- 4-dichlorophenyD-1- oxazolidine. isopropylurea.

17 2-(3,4dichlorophenyll-(nbutyl)-1-(2-ehlo- 32.4

imino)-3 -n-butylroethyl)-3-(3,4-dioxazolidlne. chlorophenyDurea.

Percent Substituted oxazolidine 50 Synthetic calcium silicate (MicroceP805) 48.25 Alkyl aryl sulfonate 1.50 Methyl cellulose 0.25

These wettable powder herbicidal compositions when extended with waterto form sprayable formulations containing 1% by weight of the activeingredient, and sprayed at a dosage of 50 lbs. per acre upon areasinfested with Johnson grass, other perennial weeds and annual weeds,give excellent weed control.

Example 17 54.5 parts by weight of1-(2-chloroethy1)-3-(3,4-dichlorophenyl)-1-methylurea is dissolved in 75parts by weight of alcohol. This is added to a solution of 12.7 parts byweight of 85% potassium hydroxide in 200'parts by weight alcohol. Themixture is refluxed for two hours and the ethanol removed byevaporation.

The residue, comprising 2-(3,4-dichlorophenylimino)- S-methyloxazolidineand 3-(3,4-dichlorophenyl)-1-methyI-Z-imidazolidinone, is washed with alittle water to remove the potassium hydroxide, and is dried to give anextremely useful herbicidally active material.

This active material is formulated into a dust composition in accordancewith the procedure of Example 3 by replacing the active ingredient ofthe composition of Example 3 with a like amount of this active material.

When applied to the ground along a railroad right of way at the rate of50 pounds/ acre of the active material, a quick 'kill of broadleaf andgrassy weeds with prolonged soil sterility is obtained.

I claim:

1. A method for the control of undesiredvegeta-tion comprising applyingto the locus to be treated, in an amount suflicient to exert herbicidalaction, the compound represented by the formula wherein X and Y areselected from the group consisting of hydrogen, halogen, and alkylgroups containing less than 5 carbon atoms, in is a positive integerless than 4; R R R and R are selected from the group consisting ofhydrogen and methyl; and R .is selected from the group consisting'ofalkyl radicals containing less than 5 carbon atoms.

2. A herbicidalcomposition comprising a herbicidal adjuvant, and inamount sufiicient to exert herbicidal action, a compound represented bythe formula wherein X and Y are selected from the group consisting ofhydrogen, halogen, and alkyl groups containing less than 5 carbon atoms;m is a positive integer less than 4; R R R and R are selected from thegroup consisting of hydrogen and methyl; and R is selected from thegroup consisting of alkyl radicals containing less than 5 carbon atoms.

3. A substituted oxazolidine represented by the formula 2 01 3N-R 15 4|G-G RI. 2 1 1a 4 wherein X and Y are selected from the group consistingof hydrogen, halogen, and alkyl groups containing less than 5 carbonatoms; m is a positive integer less than 4; R R R and R are selectedfrom the group consisting of hydrogen and methyl; and R is selected fromthe group consisting of alkyl radicals containing less than 5 carbonatoms.

4. A substituted oxazolidine as set forth in claim 3 wherein R ismethyl.

5. A substituted oxazolidine as set forth in claim 4 wherein Y ishydrogen and X is halogen.

References'Cited in the file of this patent UNITED STATES PATENTS2,396,513 Jones Feb. 12, 1946 FOREIGN PATENTS 694,133 Germany July26,1940

OTHER REFERENCES Agriculture Handbook, No. 69, page 250 (May 1954).

1. A METHOD FOR THE CONTROL OF UNDESIRED VEGETATION COMPRISING APPLYINGTO THE LOCUS TO BE TREATED, IN AN AMOUNT SUFFICIENT TO EXERT HERBICIDALACTION, THE COMPOUND REPRESENTED BY THE FORMULA
 3. A SUBSTITUTEDOXAZOLIDINE REPRESENTED BY THE FORMULA